The following are true about the ERG:
a. in infarction of the choroidal circulation the a-wave of the ERG is reduced or absent
b. the ERG is always abnormal in patients with macular diseases
c. flicker ERG can be used to isolate cone photoreceptors
d. the b-wave of ERG is reduced in dark-adapted eye
a. in infarction of the choroidal circulation the a-wave of the ERG is reduced or absent
b. the ERG is always abnormal in patients with macular diseases
c. flicker ERG can be used to isolate cone photoreceptors
d. the b-wave of ERG is reduced in dark-adapted eye